Ellie Jones, 16, began stumbling, swaying and shaking after taking PMA - an amphetamine-related substance - with other teenagers at a 3am party.

Her condition deteriorated after being helped to bed and she was rushed to hospital, but died an hour later.

It is feared she may have fallen victim to a "delayed onset" by the drug, which had been wrapped inside pieces of cigarette paper.

A 17-year-old boy, who cannot be named for legal reasons, is standing trial at Halton Youth Court accused of supplying Ellie and another teenager with PMA on the night of the tragedy in May 2013 in Warrington, Chershire.

The court heard how Ellie, a former pupil of St Gregory's High School, was overheard talking to the defendant about "only having a fiver on her" - with him replying to give her "the other fiver" the next day.

He the left the group for a few minutes claiming he was "nipping round the corner".

The boy was later seen with a clear plastic bag containing white powder and began offering the substance to Ellie and others at the party, it was claimed.

They then swallowed the substance in a cigarette paper "bomb".

A 17-year-old witness, known as Boy A, told the court the defendant told him the drug was "Whizz" - the street name for Speed - and said Ellie had taken "plenty" of bombs.

He said Ellie could have taken "seven or eight" and saw the defendant hand it over to her "several times".

He said: "Every time he had one she matched it. She just seemed like, drunk, like she was sleepy."

He told the court the group started panicking after Ellie became "agitated" and "restless" before fitting for 20 minutes.

Boy A added: "They were saying 'It's like she is possessed, she is possessed.'

"I'm sure I grabbed somebody's phone and as I called them, Ellie stopped breathing."

The witness said the defendant, who denies supplying Class A drugs, was sleeping in the other room as Ellie's condition worsened and started foaming at the mouth.

"As soon as the paramedics arrived I went. I didn't know that she was going to die.", he added.

Prosecutor Miss Wendy Newton said Ellie and the defendant were described as looking "increasingly intoxicated" as the evening went on".

Tests showed Ellie, who died at 4.49am after arriving at Warrington Hospital at 3.30am, had levels of PMA in her blood "within the range associated with fatalities from the drug".

A vodka bottle seized at the scene was found to contained alcohol and PMA.

The defendant was one of three 16-year-old boys arrested over the tragedy.